The construction industry is increasing its focus on the survivability of buildings under extreme loads from seismic events and other forces, and modern codes are increasingly focusing on the ability of the components of the buildings to resist the loads of earthquakes, while not only withstanding and transmitting the loads, but also absorbing and dissipating such loads.
Various systems have been used to reinforce building portal openings and building walls include moment frames, systems having springs, electro-mechanical damping and building isolation systems.
For example, the Simpson StrongWall® is a system typically used for reinforcing walls and portal openings in a building. It is a pre-build shear wall that may be incorporated into a building structure. Preferably, two such StrongWalls® are used, with a StrongWall® positioned on either side of the portal opening. A header beam is connected to the top ends of these two StrongWalls®. Unfortunately, the Simpson StrongWall® system has a number of disadvantages, including the fact that it must resist strong overturning moments due to its high height to width ratio. In addition, the StrongWall® system requires a variety of connectors and it incorporates a number of internal reinforcements, making it a complex and bulky system.
A typical reinforced brace frame is also made by Hardy Industries of Ventura Calif. The Hardy Frame® is a metal frame equivalent of the Simpson Strong Wall® factory-build wooden shear wall. The Hardy Frame® specifically includes a diagonal member with spaced vertical support members to provide increased resistance against simultaneous shear stress and uplifting.
As will be explained, the present invention is capable of simultaneously performing all of the functions required by the present codes, but also the energy dissipation required for better building survival, as projected in proposed codes currently under development such as AR215.